Thermal insulation vacuum panels are known in the art.
One such panel is disclosed in U.S. Pat. No. 2,768,046. That panel comprises a metal shell or envelope formed from a pan-shaped metal sheet and a generally flat metal sheet. The sheets are welded to one another at their abutting outer edges. The edges define a flange which extends about the outer periphery of the panel. The space between the two sheets is filled with glass fiber insulation and the enclosed spaced is evacuated to a very low pressure.
The patentee teaches incorporating a plurality of his panels into a refrigerator cabinet. He notes in column 1, lines 45-49 of the '046 patent that heat transfer can occur from one wall or sheet of the panel to the other at the abutting edges of the sheets. In an attempt to minimize the effect of such edge leakage, the patentee teaches providing glass fiber insulation in areas adjacent to the edges of the panels.
Vacuum insulation panels having uniform edge dimensions can be difficult to manufacture. Dimensional error may occur during one or more of the following manufacturing operations: cutting or otherwise forming the first and second sections of the metal envelope, positioning the two sections adjacent to one another and welding their abutting edges together, and evacuating the envelope.
Since these panels have thin peripheral flanges, these panels have also been found difficult to handle and transport. Finally, because the panels are formed in part by a metal envelope, it is costly to make available to the end user a large selection of panel sizes.
Accordingly, there is a need in the art for a thermal insulation vacuum panel which has improved thermal performance, can be manufactured so as to have uniform edge dimensions, can be easily manufactured in a number of panel sizes, and permits it to be easily and safely handled and transported.